1. Field of the invention
This invention relates to a switch device which is suitable, for instance for an automobile's power window regulator
2. Related art
A conventional switch device for an automobile's power window regulator, as shown in FIGS. 6 and 7, comprises a plastic switch body 1, and a plastic operating knob 13. The plastic switch body 1 includes a pair of supporting walls 2 and 2 on the right and left side of the switch body 1 as viewed in FIG. 7. The outer surfaces of the supporting walls 2 include a pair of protrusions 3 and 3 are formed, respectively. The plastic operating knob 13 is in the form of a cap extended in the front-to-rear direction of the switch device. The operating knob 13 includes right and left walls which have a pair of engaging holes 5 and 5, respectively. The operating knob 13 is rockingly coupled to the switch body 1 with the protrusions 3 engaged with the engaging holes 5.degree..
As shown in FIG. 7, an articulation surface 19 is formed in the rear surface of the operating knob 13. The switch body 1 further includes an accommodating portion 7 at the center which is in the form of a rectangular pipe section. An articulation piece 15 and a coil spring 28 are set in the accommodating portion 7 in such a manner that the articulation piece 15 is pushed against the articulation surface 19 by the elastic force of the coil spring 28. The operating knob 13 is coupled to a pusher (not shown), so that when the pusher is rocked, a window-opening switch and a window-closing switch are turned on and off.
The operating knob 13 is normally held at the neutral position by the cooperation of the articulation piece 15 and the articulation surface 19. When, under this condition, the operator depresses the left end portion of the operating knob 13 as viewed in FIG. 6, the operating knob 13 is turned about the protrusions 3 (in the engaging holes 5) in the direction of the arrow A, to turn on the window-opening (lowering) switch. When the operator releases the operating knob 13, the operating knob 13 is returned to the neutral position, and the switch is turned off. When the operator pulls the left end portion of the operating knob 13 upwardly by using a recess 4a formed in the operating knob 13, the operating knob 13 is turned in the direction of the arrow B, so that the window-closing (lifting) switch is turned on.
The conventional switch device suffers from the following difficulty: The operating knob 13 is rockingly coupled to the switch body 1 with the protrusions 3 engaged with the engaging holes 5. Hence, if the operating knob 13 is operated with an excessively great force, then it may readily come off the switch body 1, especially when the operating knob 13 is pulled upwardly.